Why some people sleep less than others

Published: Thursday, September 17, 2009, 13:25 [IST]

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Washington, Sept 17 (ANI): An international team of researchers has identified a genetic variation that lets people sleep less than others without even affecting their energy level or ability to function.

The discovery arose after a 68-year-old woman contacted Dr Christopher R. Jones, associate professor of neurology at the U of U School of Medicine, director of the University's Sleep-Wake Centre, to volunteer for sleep research.

Both the woman and her daughter go to bed between 10 and 10:30 p.m. and wake up between 4 and 4:30 in the morning and yet, their 18-hour day does not affect their energy level or ability to function.

"The mom is very energetic and extremely active. In fact, it makes me feel tired to hear about the activities she does every day," Jones said.

After examining the elderly woman's DNA, the researchers identified the DEC2 variation.

"We're all different in many ways, and sleep is one of them," said Jones, study's co-author.

"There may be some people who can function more productively with less sleep," he added.

The researchers further transferred the gene into mice to create a colony of "insomniac" rodents.

Like humans with the variation, which is called DEC2, mice who received the variant gene appeared to function normally even though they got less sleep than a control group that didn't have the DEC2 variation.

The researchers precisely monitored when the mice were slumbering, and then interrupted their sleep cycle to see how it would affect them.

Even with less sleep, the insomniac mice were more active than a group of control mice who didn't have the DEC2 variation.